Method



w. c. ANDREWS.

METHOD 0F PRODUCING GUN BARRELS.

APPLICATION FILED JAN.I1, l9l7.

344 vente@ William C-Awws Patented 'Dea 9 Llll.

To all whom t may concern:

"UNITED sTATEs PATENT onirica,

WILLIAM C. ANDREWS, OF CLEVELAND, OHIO, ASSIGNOR TO HARRY A. AUER, OF

CLEVELAND, OHIO. V

Specication ci Letters Patent'.

I Patented Dec. 9, 1919.

Original application led January 21, 1916, Serial No. 73,355. Divided and this application filed January 11,

Be it known that I, WILLIAM C. ANDREWS, citizen of the -United States, residing at Cleveland, in the county of Cuyahoga and State of Ohio, have invented certain new and useful Improvements in Methods -of Producing Gun-Barrels, of which the following is a specification.

My invention relates'to a new and improved method of producing a gun barrel in a rapid and efficient way, which consists ferent sizes. the use of a special machine, proceed slowly,

in finishing the rough bore of a gun by a series of actions involving the use of various mechanisms but not confined to one, substantially as herein shown and described and more particularly pointed out. in the claims. Ileretofore the practice has been to roughly bore the barrel, that is, to drill a round: opening lengthwise through the barrel to a predetermined diameter several thousandths of an inch less than the caliber of final desire. The next step or series of steps consisted in enlarging and smoothing the rough bore to the required caliber or diameter by a circular cross cutting action, using a rotary cutting tool or rean'xer, or by the successive use of a series of rotatable reamers of dif- Reaming operations involve cause warping of the barrel necessitating straightening before riiiing operations, and produce cuts or circular lines, ribs or scratches transversely in the finished bore. The next step involves rifling of the gun barrel; that is, a series of spiral grooves are produced longitudinally of the gun bore vby a second machine employing a draw cutting or scraping tool. When the grooving operation is finished a series of narrow spiral lands have been developed upon which the cross cuts of reaming operations are often visible to the naked eye notwithstanding that the reaming operation is supposed to smooth the bore and does do .so except for the defects noted. A final dressing operation is sometimes resorted to as a last step to cure the defects of reaming, but thisin turn is detrimental to the land edges which vshould remain sharply cut to operate at their maximum efficiency in rotating the bullet in its course through the barrel. Having these old steps and results in mind, the object of my invention is two-fold, first, to produce an improved rifle barrel without objection- 1917. Serial No. 141,744.

able internal faults, and second to produce a r1fle barrel by simpler, speedier and more econonncal steps than as practised heretofore..` That is to say, the steps taken by me ehmmate the old reaming operation entirely and the objectionable cross cuts altogether, while the rifling and finishing operations of the bore may be performed in one and the same machine instead of separate machines as heretofore, and where the former practice was to enlarge the bore to its truev caliber as a first step and to rifle the enlarged bore as a second step, I prefer to reverse the sequence of actions by first rifling the barrel in its roughly-'bored state, and secondly, enlarging and smoothinr the rilied rough bore to its true-caliber. n effect, the finishing and snloothing of the rough bore is to enlarge the bore, which I accomplish by a series of cutting actions, each continuously applied on elongated spiral lines lengthwise of the bore, and therefore I am enabled also to perform this finishing and enlarging operation of the bore during the final steps and stages of rifling on lines coinciding with the spiral grooves. That-is, with one form of tool which I may use the final steps of rifling the bor'e and the enlargement thereof to a predetermined smoothness and caliber proceed simultaneously. Such a tool is shown and described in my co-pending application, filed January 21, 1916, Ser. No. 73355, of which this application is a division, but I do not restrict myself to the 'use of this specific tool in practising my invention. In fact, the method is not absolutely dependent upon a machine or any particular tool, but as it is best illustrated and practised by mechanism, the accompanying drawings serve to show one form of mechanism with which to practice this method in general and a specific mode of operation also. V

Thus, in Figure 1, I show a plan view of a cutting tool or rifling head (substantially full size) entering one end of a gun barrel as at the start of operations. Fig. 2 illustrates an enlarged face View of a cutter tudinally of the tool in a .plane at right angles to Fig. 3. Fig. 6 is a longitudinal section of a finished rifie barrel, Figs. 7 to' 1:2, inclusive are transverse sections of a gun barrel and the tool o n linea-, Flg. 3, showing various stages 1n rnling and bore lenlarging operations, as hereinafter more fully described. t

The tool shown comprises a cylindrical head -A- which is of approximately the same diameter as the rough-bore of the gun barrel B so as to move freely therein, and this head is tubular and afiixed to a rod 2 which is rotated and reciprocated simultaneously in rifling operations by automatlc mechanism of any suitable character and kind known to those skilled in the art. That is, the tool is adapted to be used in any known machine for ritling gun barrels wherein the barrel is held stationary at intervals while cutting proceeds, and also rotated a definite number of degrees at intermittent intervals while the cut-ting tool is projected -out of the barrel, these operations proceeding automatically as usual for the purpose of producing a series of collateral grooves and lands within the barrel according to any desired or accepted standard. For example, the present tool is designed to produce four grooves and lands, and the rod 2 is reciprocated and rotated automatically by the machine to produce a spiral cut of gradual inclination, the tool being given one revolution in approximately'each ten inches of longitudinal travel thereof throughout the length of the gun barrel while the barrel remains fixed and stationary. Each spiral cut removes a very thm ribbon or shaving and is obtained by drawing the tool through the barrel until it emerges therefrom, and then the cutters are collapsed before returning the tool through theJ barrel to repeat the operation. Four such draw cutting movements of the tool and four rotative movements of ninety degrees each of the barrel produce four rifling grooves or channels of the same depth but this depth is only a fraction of the depth required as it is not desirable nor practicable to cut each groove the full depth in a single draw eut, notwithstanding that the full depth of such a groove is usually only several thousandths of an inch. Consequently, repeated draw cuts are made until the grooves reach the required depth, and to do this the cutters are expanded automatically subsequent to each complete revolution of the gun barrel and following the fractional cutting of four grooves of equal width successively to the same depth. The number of times that such operations are repeated is dependent upon the number and depth of the rifling grooves and lands desired, but the last series of cutting actions finish the faces of the spiral lands as Well as the spiral grooves, thereby enlarging the rough bore to the final caliber desired by a planing movement coinciding exactly in direction to the spiral grooves produced in the bore, in this Way cutting all the contiguous surfaces of the bore on coinciding spiral lines, the spiral being relatively elongated or of extreme obtuse pitch.

In these opera-tions, a pair of hook cutters 3 and 1 may be used and related in a particular way to produce a plurality of cuts in each draw stroke'of the tool A an overlapping [cuts as well ini successive draw strokes, all without injury to the lands 5 produced in the barrel by such series of actions. Thus, in one form of tool the cutters 3 and etmay be of equal Width and each have a curved draw cutting edge 6 conforming to the extreme diameter of bore desired measured to the bottom of the rifling grooves. The width of such cutters is more or less dependent upon the width of the lands 5 or the number of lands to be produced, and in the tool shown, cutter 3 is provided with a longitudinal channel 8 in its face 7 corresponding in width to the land to be made, and the channel 8 extends into the vertical or undercut shoulder which is crowned at each side of the channel by the cutting edge 6. Accordingly the cutting edge in cutter 3 is stepped and of the same outline as the channeled surface 7, and the end edge at the base of the channel provides aland planing edge 6 at a point relatively nearer the center of the tool than the double groove cutting edges 6. Compared therewith, cutter -l is plain or of regular curvature to pron duce a single groove, and in the tool shown these two cutters are confined Within longitudinal slots 9 placed approximately onehundred and thirty-live degrees apart measured center to center radially of the tool. Moreover, each cutter has a beveled end 10 to engage the undercut end 11 of its corresponding slot 9, and a spring stem 12 for each cutter extends lengthwise of each slot into bearing engagement with the socket end 13 of a spring-pressed plunger 14 which is adapted to slide Within a round opening extending centrally through cylindrical head A. The coiled spring 15 which is sleeved over the reduced extension 16 of plunger 1-1 is backed by a cross pin 17 in head A, and a conical projection 18 is provided centrally Within the socket end 13 of the plunger to hold the cutter stems 12 centrally in place. Each cutter member is also provided with a beveled face 19 opposite its cutting face 7, and these beveled faces 19 are opposed and engaged by the corresponding beveled surfaces 20 of a Wedge member 21 reciproc'ally confined within the smooth round opening Within the head A. An inward ino-vement of Wedge member 21 expands the cutters uniformly, that is, forces them outwardly radially of the head notwithstanding the resistance offered by the end seating relations of each cutter with the undercut ends 11 of slots 9. Such resistance is overcome by the end thrust upon-said cutter members and the yielding action of the spring-pressed plunger 14. The inward movement of wedge member 21 is limited by an enlargement 22 on the outer end of the round operating stem 23 striking the squared extremity 24 of a split screw plug 25-which is adjustable longitudinally within the screw threaded end of headA, and the inner extremity of this screw plug limits the outward Ior retiring movement of the Wedge member 21 relatively to the cutters when these are to be collapsed for the return or idle stroke of head A. The outward movement of wedge member 2l is eii'ected by a projecting pin or screw 26 located at the bottom of member 21 Whena suitable stop or operating part in the machine is reached and engaged during reciprocal movements of the tool. This screw 26 works back and forth in a longitudinal slot 27 at the bottom of head Aand functions also to hold wedge member 21 from turning Within the head. Undue play or looseness of head A is prevented within the bore of the gun barrel B durlng entering and cutting operations by means of a pair .of wire bow springs 28 socketed at their ends with a limited play within oppositelyinclined holes within the upper side ofthe cylindrical head A.

Now referring to Figs. 7 to 12, these views illustrate a series of steps in riiii-ng a -gun barrel with a tool as shown, whereby four spiral gmoves and lands are produced, but it must be understood that complete riiing is not performed in the single series of steps illustrated but that substantially the same cycle of operations is repeated many times to cut the grooves to their full depth and to plane and smooth the lands. hus beginning with the gun barrel in its roughly-bored state and ,omitting the usual step of reaming the bore in a separate machine, I insert the riling header tool A within the gun barrel and pass the itool through the bore of the barrel with the cutters 3 and 4 collapsed, a condition and relationship of parts illustrated in Fig. 7. The tool is projected more or less beyond the end of the barrel, say substantially as shown in Fig. 1, and the cutters 3 and :4 expanded by Wedge member 21 and positioned to produce the first light cut while the gun barrel is held stationa-ry and the rod 2 reeiprocated and rotated simultaneously by the usual means found in any ordinary rifling machine. The'first lightl cut is relatively not as deep as shown in Fig. 8, but'this vie'W serves to illustrate the operation, which consists in grooving the rough bore of the barrel in a plurality of places approximately one hundred and thirty-five degrees apart radially of the barrel, and in the presentcase cutter '3 at the left produces a double groove and leaves a rough land portion 5 centrally opposite the longitudinal channel 8 in said cutter, while cutter 4 at the right forms va single groove a the full Width of the cutter. Cutting at this depth proceeds t-he full length of the barrel and a thin shaving is removed by drawing the tool through the barrel While rotating the tool at the same time the desired number of times to produce a spiral cut of gradual inclination relatively to the axis of the barrel. At the end of this movement, the cutters are collapsed by retiring the wedge member '21 and the tool is retui-nedto the opposite end of the gun barrel for the next cut, which does not begin however until the barrel B has been given a quarter turn as indicated by the arrow in F ig. 8 and which turned position of the barrel is shown -in Fig. 9 a-nd may be effected by hand or mechanism.

iVith the parts related in this way a. second cutting action proceeds as before, the position of cutter 4 at the right producing a second wide groove in the barrel at a pointI intermediate the first-made land portion 5 and the first-made wide groove u, and it should be noted that cut-ter 4 is Wide enough and the turned position of the barrel sulicient to cause cutter 4 to overlap the right border of the divided groove which has been cut previously by cutter 3 and that the land portion 5 centrally within said divided or double cut c by cut ter* 3 is cleared by a safe margin from cutter 4 during the second cutting step as shown in Fig. 9. Manifest-ly, this second cutting step involves the production of a second land portion 5 and a divided or double groove (Z by cutter 3 at the left, sec Fig. 9.-

The reciprocal movements of the tool and the collapsing and expanding movements of the cutters being understood, suflice to say that the third cutting step of the cutters is illustrated in Fig. 10, a position of parts established by rotation of the gun lbarrel ninety degrees in the direction shown by the arrowr in Fig. 9 and from the position of the barrel i-n that figure to the advanced position in Fig. 10. Here the land portion 5 of the divided groove c is advanced safely beyond the reach of cutter 4 and the newlymade land portion 5 centrally in the di vided groove ai is also clear of said cutter 4 While at the same time said cutter is in overlapping cutting relation with both grooves c and d to remove the stock completely between the land portions, the stock removed by cutter 4 being indicated at c in Fig. 9. A third land portion 5 and divided groove f is also being cut by cutter 3 While this stock e is being removed by cutter ,4, and cutter 3 now produces an overlapping cut also at one border of the groove a Where it has been advanced Within the reach of said cutter 3, see Fig. 10. Three land portions -5 have been clearly defined and cut to their final Width at this stage of operations, and a segment of stock g has been left undisturbed between grooves a and b, see Fig. 10, from Which the fourth land portion is produced in the next or fourth cutting step, see Fig. 11, Where the barrel B has been given its last quarter turn following the completion of the cutting step shown in Fig. 10. In Fig. 11, all four land portions 5 are shown and all the stock removed between such land portions to a uniform depth, cutter 4 in this last stage serving to remove the stock designated by h in Fig. 10, and the cutter 3 removing the surplus stock g at each side of the fourth land portion .5 as explained.

In all these successive steps or cycle of operations for producing the four lands and a f 'actional grooving cut of uniform depth between the lands, the circular surface of each land defined by the rough bore of the gun barrel is not engaged nor cut by the cutting edge 6 at the base end of the channel 8 1n cutter 3, and it is not until these series of steps or cycle of operations have beenrepeated a number of times and the full depth or substantially the full depth and filial cuts have been reached' by expanding the Cutters repeatedly that such land surfaces are engaged and cut by the cutting edge 6 of cutter 3, see Fig. 12. Thus finally, each successive movement of the tool through the barrel effects a supplemental cut lengthwise of the face of the spiral land, beginning with a planing action on the rough surface as found originally, and proceeding with successive planing and smoothing actions lengthwise of each land on elongated spiral lines coinciding exactly -with the collateral spiral grooves until the full depth of groove desired is reached and ythe true and desiredI caliber of bore is obtained. It follows also that the final cutting steps involved in producing the spiral grooves and the enlargement and smoothing of the bore proceed simultaneously, and to reach the desired depth of groove and a predetermined caliber of bore the cutters 3 and 4 are expanded by degrees, preferably after each cycle of operations as defined by four successive quarterly rotations of barrel B, such expansion being effected by apartial rotation of screw plug 25 through its squared extremity 24 and a step-by-step inward movement of wedge member 21. To obtain these results automatically the machine using this tool is designed to have a stop to engage the stem enlargement 22 of member 21 and effect the inward movement i'ng a rified gun barrel of a predetermined caliber consists primarily in planing all of the contiguous curved surfaces ofthe bore of the gun repeatedly on coinciding spiral lines of gradual imlination relatively to the axis of the bore until a predetermined caliber is obtained, regardless of any particular sequence of steps taken. `In a more limited sense, the invention consists in planing a series of collateral grooves to apredetermined width and depth spirally within a gun barrel and then planing the land faces between the grooves on spiral lines corre spending exactly with the spiral grooves until a predetermined caliber of bore is obtained. Still more specifically, the invention consists in planing a series of grooves spirally within a gun barrel and simultaneously at some stage of this operation. preferably the filial stage, planing the land portions on corresponding spiral lines until a predetermined caliber of bore and depth of groove is obtained. Other steps subordinate to the foregoing are* also involved all as hereinbefore described in detail, but in every instance the product of mv method is superior to the product of other methods in which reaming is an essential 'step in that if there be any scratch` mark, or irregularity of cut in the bore that such scratch, mark or irregularity, whether infinitely small or plainly visible. shall extend longitudinal v of the bore and coincide with the spiral grooves or rifling instead of being at an angle or counter thereto to impede the course of a bullet and cause foul- 'ing of the gun in use.

What I claim is;

1. A method of rifling and smoothing a gun barrel bore, consisting in first planing rifle grooves in the rough bore surface of the gun barrel, and secondly, enlarging and smoothing the unplaned portions of the rough bore to a predetermined caliber.

2. A method of rifling and smoothing a gun barrel bore, consisting in planing rifle grooves in the rough bore of a gun barrel and enlarging the roughbore to a predetermined smoothness and caliber concurrently.

3. A method of producing a rifled gun barrel bore of a predetermined smoothness and caliber, consisting in boring the gun planing the circular of a gun barrel, consisting in planin all of the contiguous curved surface of t e bore repeatedly on relatively elongated spiral lines until a predetermined caliber is obtained.

5. A method of finishing the rough bore of a gun barrel, consisting in planing contiguous segmental surface portions of the bore repeatedly on identical elongated' spiral lines lengthwise of the bore until the entire circular surface of the bore has been enlarged.

6. A method of smoothing and rii'ling a gun barrel bore, consisting in laning a series of radial grooves to a pre etermined width and depth spirally within the circular bore surface and then planing the radial land faces between the grooves on spiral lines corresponding exactly with the spiral grooves until a predetermined caliber of bore is obtained.

7. A method of riin and smoothing the rough bore of a gun arrel, consisting in surface of the bore at different places radially thereof and successively until a series ofgrooves of a predetermined depth are obtained, the planing actions proceeding on identical spiral lines extending lengthwise of the bore and being repeated lengthwise of the remaining unplaned surfaces of the bore until a predetermined smooth caliber is obtained.

8. A method of rifling and enlarging the rough bore of a gun barrel, consisting 1n removing a thin shaving from the rough bore surface successively at different radial points of 'the bore by a cutting action proceeding lengthwise of the bore on parallel spiral lines and repeating said cutting actions until a series of grooves of predetermined depth have been formed, and finally duplicating such cutting actions over the rough uncut segmental portions of the bore until a smooth rifled bore of predetermined caliber is obtained.

9. A method of rifling and enlarging the rough bore of a gun barrel, consisting in planing a series of grooves radially and spirally within the rough bore surface, and simultaneously planing the land faces between the grooves on corresponding spiral lines until a predetermined caliber of bore and depth of groove is obtained.

10. A method of rifling and enlarging the rough bore of a gun barrel, consisting in grooving the circular surface of the rough bore at different circumferential places therein.simultaneously by a series of cutting actions moving on corresponding spiral lines longitudinally of the bore, and then planing the uncut segmental portions of the bore surfaces by continuing said cutting actions until a smooth rifled bore of predetermined caliber is obtained.

11. A method of rifling the bore of a gun barrel, consisting in removing segmental surface portions of the bore simultaneously in adjoining areas thereof by a double cutting action moving in a'longitudinal direction on identical spiral lines, then repeating the same cutting actions with an overlapping cut in different radial places successively in the circular bore surface; and then continuing the spiral cutting action over the uncut segmental portions of the bore surfaces until a predetermined caliber of bore is obtained.

12. A method of producing a rifled gun barrel of a predetermined caliber, consisting in planing the rough bore by successive planing actions moving lengthwise of the bore on corresponding spiral lines and in a plurality of adjoining places simultaneously, continuing such cutting actions to diii'erent depths at different places in the circumference of said bore until a series of spiral grooves and lands have been produced, and finally planing the land surfaces by similar cutting actions until a smooth riiied bore of a predetermined caliber is obtained.

13. A method of riliing a gun barrel, consisting in cutting a series of grooves spirally in the curved surface of the gun bore, by a series of successive cutting actions, each advancing on corresponding curved lines side by side and limited to a fraction of the depth and width of groove to be produced, and cach succeeding cutting action advancing in an overlapping relation to widen the groove previously cut.

Signed at Cleveland, in the county of Cuyahoga and State of Ohio, this 28th day of December. 1916.

WILLIAM C. ANDREWS. 

